Some owners of the new Ford Mustang Mach-E electric crossovers are facing a particular problem. Their electric cars refuse to run despite a fully charged main battery. As The Verge found out, this is due to the charging mechanism of the 12-volt battery used to power some parts of the car.
Mustang Mach-E is equipped with two batteries: traction lithium with high voltage for powering electric motors, and also 12-volt lead-acid, which is more usual for cars, for powering many systems, such as lighting. A Ford EV keeps its 12-volt battery charged by consuming power from the main battery. According to the owners, the small battery for some reason consumes energy every time the electric car is connected to the network to charge the main battery. Electric vehicle owners in cold climates are particularly affected by this issue, as Ford recommends that they leave their Mustang Mach-E plugged into a charger to warm up before driving.
The 12-volt battery powers nearly all Mach-E systems, so when it is discharged, the vehicle won’t start and the FordPass app tells it to be in deep sleep. Some users have already dubbed this problem “Electric Brick”.
Ford recently filed a maintenance bulletin with the US National Highway Traffic Safety Administration, confirming that the problem is with the transmission control module software. The company said it only applies to Mustang Mach-E manufactured up to and including February 3rd, which is roughly a few dozen electric vehicles.
Interestingly, owners of defective vehicles cannot receive a software patch wirelessly. To do this, they need to deliver their electric car to an authorized dealer, which in itself may not be very convenient. Ford says it will release a wireless update later this year that may fix the problem. The company says that copies released after February 3rd are not affected by this issue.
Of course, if you need to urgently solve the problem, you can replace the 12-volt battery with a charged one, but this will require a number of actions that are likely to scare off inexperienced vehicle owners. The thing is that the battery is located behind the front trunk, which is locked with a lock, which is powered by the same battery. Therefore, to access the battery, you will have to open the panel in the front bumper and gain access to the wires that allow you to open the cover in a roundabout way. However, access to the battery terminals is impeded by the vehicle design, and some users have to cut the vinyl to get to them.
Of course, Ford offers free roadside assistance to electric vehicle owners, which includes starting the vehicle from a 12-volt battery and the ability to tow the Mustang Mach-E to the dealer.
If you notice an error, select it with the mouse and press CTRL + ENTER.